The following United States patents are the closest prior art known to the inventor: Nos.
1,508,860 PA1 2,016,164 PA1 2,028,298 PA1 2,451,629 PA1 2,879,976 PA1 3,228,460 PA1 3,409,075
These prior art patents generally disclose heat exchanger devices which employ perforated plates or members as heat exchanging elements. All of these devices may be characterized by the fact that the heat exchanging elements are perforated in random fashion, and are oriented randomly in the heat exchanging assembly.
In these prior art devices, the perforated heat exchanging members are assembled to facilitate the flow of a pressurized fluid in an axial direction therethrough. The fluid flow through the randomly oriented members causes the fluid to be exposed to a rather large surface area, and this high surface exposure provides ample opportunity for the fluid to exchange thermal energy with the perforated members. The result is a fairly efficient heat exchanger which is quite suitable for many purposes.
In the specific application of the heat exhanger of a Stirling cycle engine, it is necessary to have the highest possible heat transfer rate with a very low volume of gas in the heat exchanger and a minimum of impedance to the flow of gas. Due to the randomness of the orientation of the perforated heat exchanging members in the prior art devices, this is not possible. If the perforations of the multiple heat exchanging members are substantially aligned, the flow of fluid is maximized and there is very little impedance of this flow.
On the other hand, if the perforations of the heat transfer members are substantially mis-aligned, the axial flow is completely interrupted and the flow impedance is thus quite high. In this case, the flow impedance would be a substantial factor affecting the performance of the Stirling cycle engine.